PROJECT SUMMARY Parkinson?s disease (PD) is a progressive neurodegenerative brain disorder affecting at least 10 million people worldwide. The cardinal motor impairments are tremor, bradykinesia, muscle rigidity, and postural instability. It has been shown that postural instability in people with PD often responds insufficiently to dopaminergic medication and surgical treatment, which in turn results in loss of balance, risk of falling, and adverse effects on quality of life. PD is commonly managed in outpatient neurology or movement disorder clinics. Numerous studies have examined the beneficial effects of physical and balance rehabilitation regimens to improve postural stability in people with PD. Unfortunately, many challenges (e.g., cost, limited availability of physical therapists, limited access to clinical facilities, compliance with prescribed exercises, etc.) restrict participation in the clinical and home settings. Smartphone-based telerehabilitation technology can provide an alternative to assist people with PD in performing in-home balance rehabilitation exercises. Having developed the first smartphone-based vibrotactile biofeedback system for static standing exercises, recently, the PI developed and assessed an advanced prototype, called Smarter Balance System (SBS), for use by people with PD performing physical therapists? recommended dynamic balance exercises over short periods (less than an hour) in a laboratory setting and long periods (6 consecutive weeks) in a home setting. The SBS, consisting of a smartphone and a wearable belt, supports multimodal (visual and touch) biofeedback as assistive guidance and provides real- time error magnitudes for the dynamic weight-shifting balance exercisesrecommended by physical therapists. The PI?s findings underscore the need to systematically evaluate persistent improvements in static/dynamic balance performance, long-term performance retention, and carry-over effects in people with PD performing in- home balance training with either the telerehabilitation regimen via the SBS or a typical paper-based regimen. Therefore, Aim 1 will assess and compare the results of the SBS and a paper-based regimen for long-term in- home rehabilitative balance training, and Aim 2 will quantitatively and qualitatively analyze the carry-over effects of long-term rehabilitative training with the SBS on static/dynamic balance performance, daily physical activities, and confidence in less fear of falling compared to a control group with a typical paper-based regimen. The proposed work will provide insights into how in-home balance training with the SBS can produce persistent improvements in balance performance, translate into beneficial effects (i.e., improved confidence in daily physical activities, reduced fear of falling, and decreased risk of falling), and give better results than typical paper-based regimens. The SBS?s user-friendly and wearable characteristics should reduce the need for in- home assistance by family members and caregivers. Physical therapy should improve as physical therapists monitor compliance with in-home balance training regimens, track exercise progress, and give suggestions remotely.